RTC AP21 Series Operation manual

OPERATION/SERVICE MANuAl
AP21
021020 /19125
RTC-TRAFFIC.COM
For Version 3.02 and higher.

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AP21 Programming Manual
AP21 TABLE OF CONTENTS
PROGRAMMING MANUAL
Introduction 1
Specifications: Electrical/Physical 1
Programming Features 1
Power Fail Backup 2
Accuracy 2
Wiring 2
AP21 Octal Base Mount Pin 2
Display and Keyboard Descriptions 3
Programming Instructions 4
Programming Sequence 4
Display and Special Key Codes 5
Time Switch Keys 5
QUICK REFERENCE PROGRAMMING GUIDE
Program/Edit Time-Of-Day 6
Program/Edit the Date 7
Program/Edit the Day-Of-Week 7
Program/Edit Daylight Saving Time 8
Program/Edit Basic Program Steps 9/10
Program/Edit Annual Plans 10/11
Activate/Deactivate Sleep Mode 12
Program/Edit Pulse Rate 12
Manual Operate the Output Relay 12
Adding Seconds to the Time Display 12
Transfer Program to another AP21 12
WARRANTY 13
SERVICE / THEORY OF OPERATION Back Cover

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AP21 Programming Manual
INTRODUCTION
The AP21 is an single circuit, calendar-programmable solid state time switch used for switching electric circuits
according to pre-set time and date program. The AP21 is primarily designed for school zone and traffic control use where
multiple daily/weekly programs are required on an annual basis. The relay output can be programmed for momentary
operation for bell or buzzer operation in schools, churches, or industrial facilities.
ELECTRICAL SPECIFICATIONS
 PowerRequirements: •95VACto135VAC,60HZ.,3VAmaximum10.5VDCto14.3VDClessthan
1 watt through full range of supply voltage (0.2 to 0.58 average)
 Outputs:  •AP21,SPDTrelayratedat15AMPresistiveat120VAC
 Wiring:   •Terminalblockcanaccommodate#12to#24AWGwire
PHYSICAL SPECIFICATIONS
 Dimensions:  •3.7”Wx8.0”Hx1.55”D
 Weight:   •Approximately2pounds
 Mounting:  •Pre-drilledmountinghole(AP21)
 OperatingTemperature: •-30˚to+74˚C
PROGRAMMING FEATURES
AUTO PROMPTING DISPLAY — The display provides information to guide the operator through programming.
Upon power-up, it will prompt the operator through setting the time and basic programming sequence.
DAY PLAN — The Day Plan is made up of the programmed steps that will take place on the assigned days and control the
output relay. The Day Plan can be assigned to all days, just week days, just weekends, or specific days of the week.
16 PROGRAM STEPS — The Day Plan can hold up to 16 program steps. The 16 program steps are used to program
ON/OFF times for the relay.
ANNUAL “SKIP” PLAN—TheAP21canholdupto10Annual“Skip”Plans,whicharedatesordaterangesthatwill
receive no programming steps. Annual plans are used for special events such as holidays or spring break, throughout the
calendarthatdifferfrom“normal”DayPlanscheduling.
PROGRAMMABLE DAYLIGHT SAVING TIME ADJUSTMENT — The AP21 automatically adjusts for daylight saving time
changes according to U.S. law. Re-programmable if law changes.
AUTOMATIC LEAP YEAR COMPENSATION —Perpetualtypecalendartoadjustfortheextradayevery4years.
TRANSFER — Allows program data to be transferred from one AP21 to another or from a computer to an AP21.
MANUAL OVERRIDE — The output relay can be manually activated or deactivated from the keyboard. The manual override
willremainineffectuntilthenextprogrammedstepoccurs.
SLEEP MODE — Deactivates relay output while maintaining all timing data during summer vacation.
PULSE OUTPUT — The output can be programmed to operate as constant contact or a momentary contact programmable
from 1 to 99 seconds.

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AP21 Programming Manual
13 N/U N/U
14 N/U N/U
15 N/U N/U
16 N/U N/U
POWER FAIL BACKUP
Program and time keeping is maintained for 48 hours on a rechargeable capacitive backup system in the event of a power
failure. The output and display are disabled during backup. The AP21 resumes normal operation when power is restored.
ACCURACY
TIME KEEPING — Synchronous with the AC power line and 4 PPM on DC power. During a power failure it is quartz crystal
controlledwithanaccuracyof+/-.005%throughoutitsfulltemperaturerange.
PROGRAMMED EVENTS — On/Off events are programmable with a one minute resolution and occur at the zero second
of that minute.
WIRING
WARNING:Disconnectpowerbeforewiringconnection.Observeallsafetyprecautions.
AP21
TERMINAL BLOCK
 AC– AC+ GND +12V –12V N/O N/C COM
Relay
Moveable
(IN)
Relay
N/O
(OUT)
PIN # WIRE COLOR
TXDOT WIRING AP2T/CPR
FUNCTION
1 Black 120 VAC
2 White AC - (Neutral)
3 Green Chassis Ground
4 Red Relay N/O
5 Yellow Relay N/O
6 N/U N/U
7 N/U N/U
8 N/U N/U
9 N/U N/U
10 White/Yellow Relay Common
11 White/Red 12V DC+
12 White/Black 12V DC Common
13 Black/Red 12V DC–
14 N/U N/U
15 Red 12V DC+
16 N/U N/U
PIN # WIRE COLOR
STANDARD WIRING AP2T/CPR
FUNCTION
1 Black/White 120 VAC
2 White AC - (Neutral)
3 Green Chassis Ground
4 Yellow/Black Relay Common
5 Yellow Relay N/O
6 N/U N/U
7 N/U N/U
8 N/U N/U
9 N/U N/U
10 Yellow/White Relay N/O
11 N/U N/U
12 N/U N/U
AP21TR OCTAL BASE MOUNT PIN OUT (discontinued product, unavailable for a new installation)
ToinstalltheAP21TRrequiresaneight-pinoctalbasesuchasaPotterandBrumeld#27E122orequivalent.Mountthis
base in a suitable location and wire the terminals of the base as follows:
AC VERSION DC VERSION
1. Relay Common 1. Relay Common
2. Line 2.
3. Relay normally open 3. Relay normally open
4. Relay normally closed 4. Relay normally closed
5. 5.
6.    6.–12VDC
7. Neutral 7.
8.    8.+12VDC

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AP21 Programming Manual
DISPLAY AND KEYBOARD DESCRIPTIONS
ALPHA-NUMERIC DISPLAY – Used for displaying time, day, date, output status and for
displaying information during programming or reviewing stored programs.
KEYBOARD – Many of the AP21 keys serve multiple functions. Those keys are clearly labeled
with their functions printed adjacent to the key. They cannot be used incorrectly as the
display will AUTO PROMPT the user as to which key to press.
AM/ON (1) KEY – Used for setting time to AM when in the time set or programming modes.
Also used for setting output to ON or OFF when in the programming mode. Also used for
setting the output to ON manually.
PM (2) KEY – Used for setting the time to PM when in the time set or
programming modes.
TIME (3) KEY – Used for entering the set time mode.
ANNUAL (A) KEY – Used for entering the annual programming mode and for stepping
through the stored annual programs for review. The annual programs contain the skip
plans in calendar schedule form.
BASIC (B) KEY – Used for entering the basic programming mode and for stepping
through the stored basic programs for review. The basic programs contain the daily
timed events instructions.
CLEAR (C) KEY – Used for clearing all annual skip plans and basic program steps.
DATE (D) KEY – Used for entering the set date mode for entering date or reviewing the date.
EXIT (#) KEY–Usedforexitingthesettime,setdate,orprogrammode.
OFF (0) KEY – Used for setting the output to OFF when in the programming mode. Also used for setting
the output to OFF manually.
STEP/ENTER (*) KEY – Used for entering all commands and for stepping through the set time, set date
or program data entry.
DST (7) KEY – Used for entering or changing the daylight savings time program.
DAY (4) KEY – Used for setting the current day of the week.
PULSE (5) KEY – Used for programming the output relay on for a specific time period (bells,
sirens, etc.).

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AP21 Programming Manual
PROGRAMMING SEQUENCE
1CREATE
DAY PLANS 2CREATE ANNUAL PLAN
•ChooseStepNumber
•ChooseTime
•ChoosetoTurnRelay
On or Off
•ChooseException
•ChooseStartDate
•ChooseEndDate
PROGRAMMING INSTRUCTIONS
THE AP21 CURSOR — On many of the AP21 display screens you will see a flashing square character called the cursor. The
cursor indicates that you may now enter or change the data at that position of the display.
AUTO PROMPT DISPLAY — On a cold start with a discharged back-up capacitor, the AP21 will automatically prompt the
operator through the programming procedure. The operator simply has to follow the display and enter the appropriate data as
thecursoradvancesthroughtheprogramentries.YoumayexitthissequenceifdesiredbypressingtheEXIT(#)keyandthe
unit will default to the time display mode. From the time display mode, you may enter any of the set time, date, or program
modes manually.
ENTERING DATA — From the cursor, you enter the appropriate data and press the ENTER () key. The cursor will automatically
advancetothenextposition.Ifthedataatthecursoriscorrect,simplypresstheENTER () key to advance the cursor. The
AP21 will not allow you to enter an invalid number (i.e., the unit will not accept the number 13 for a month entry). The cursor
will remain in its position until a valid entry is made, so keep pressing the keys until you see the correct number at the cursor
and then press the ENTER () key.

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AP21 Programming Manual
DISPLAY KEY CODES
= ENTER
WDY = Mon thru Fri
MM = month of the year
EDY = every day of the week
DD = day of the month
WND = Sat and Sun only
YY = year
HH = hour of the day
MM = minute of the hour
SUN = the Sunday of the month for DST change
1= first Sunday 4= fourth Sunday
2= second Sunday L= last Sunday
3= third Sunday
SPECIAL FUNCTION CODES
0= Manual operation is set to OFF
1= Manual operation is set to ON
7= DST (daylight saving time change)
45 = Sleep Mode (disables output relay)
77 = Clear all data for reprogramming
78 = Program transfer between AP21 units
99 = Current software version
88 = Prevents the screen from blanking
88 = again allows the screen to blank
HH : MM
— when Colon is Flashing = Display Blanking
— when Colon is Steady = Display “ON” continuously
TIME SWITCH KEYS
1= AM and ON
2= PM
3 = TIME (time-of-day)
4 = DAY (day-of-week)
5 = PULSE (pulse or steady output/s)
7 = DST (Daylight Saving Time)
0 = OFF (relay off)
A = ANNUAL (programs)
B = BASIC (programs)
C = CLEAR (clear all annual or basic programs)
D = DATE (month, day, year)
#=EXIT(exittothetimedisplaymode)
= ENTER (enter the data at the cursor)

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AP21 Programming Manual
AP21 QuICK REFERENCE PROGRAM GuIDE
NOTE: The display of the AP21 will automatically blank after about 5 minutes of keyboard inactivity, simply press any key
to reactivate the display.
Start programming from the MAIN DISPLAY.
PROGRAM THE TIME-OF-DAY
— From the MAIN DISPLAY, press key 3(TIME) then ENTER ().
Enter the time-of-day as iillustrated at right: HH MM AM/PM 
Note: = ENTER
> To Review Or Change The Time-Of-Day
From the Time Display Mode:
· Press TIME (#3) and then press ENTER (),thecursorwillbeattheHOURposition
· Press ENTER ()iftheHOURdisplayediscorrect,orkeyinthecorrectHOURandpressENTER (),
the cursor will now advance to the MINUTE position
· Press ENTER () if the MINUTE displayed is correct, or key in the correct MINUTE and press ENTER (),
the cursor will advance to the AM/PM position
· Press ENTER () if the AM/PM displayed is correct, or key in the correct AM/PM and press ENTER (),
the new time will begin and the display will return to the Time Display Mode

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AP21 Programming Manual
PROGRAM THE DAY-OF-WEEK
— From the MAIN DISPLAY, press 4(DAY) then ENTER ().
Enter the day-of-week as iillustrated at right:
Note: Press key 4(DAY) until the correct day appears.
Day-of-week 
Note: = ENTER
PROGRAM THE DATE
— From the MAIN DISPLAY, press D (DATE) then ENTER ().
Enter the date as iillustrated at right: MM DD YY 
Note: = ENTER
> To Review Or Change The Date
From the Time Display Mode:
· Press DATE (D) and then press ENTER (),thecursorwillbeattheMONTHposition
· Press ENTER ()iftheMONTHdisplayediscorrect,orkeyinthecorrectMONTHandpressENTER (),
the cursor will now advance to the DAY position
· Press ENTER () if the DAY displayed is correct, or key in the correct DAY and press ENTER (),
the cursor will advance to the YEAR position
· Press ENTER () if the YEAR displayed is correct, or key in the correct YEAR and press ENTER (),
the display will return to the Time Display Mode
> To Review Or Change The Day-Of-Week
From the Time Display Mode:
· Press DAY (#4) and then press ENTER (),thecursorwillbeattheMONTHposition
· Press ENTER ()iftheDAYOFTHEWEEKdisplayediscorrect,oradvancetothecorrectDAYOFTHEWEEKby
pressing DAY (#4)repeatedlyuntilthecorrectDAYOFTHEWEEKisdisplayed,andthenpressENTER (),
the display will return to the Time Display Mode

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AP21 Programming Manual
PROGRAM DAYLIGHT SAVING TIME (DST)
— From the MAIN DISPLAY, press key 7(DST) then ENTER ().
Enter the spring and fall Daylight Saving Time as iillustrated
at right:
Note: The AP21 will default to the current U.S. standards:
S(Spring), M = 03 (March), SUN = 2(second Sunday)
F(Spring), M = 11 (November), SUN = 1(first Sunday)
To change the month, simply key in the new month and press ENTER ().
To change to another Sunday of the month, key in the Sunday of the
desired month by entering:
1first Sunday
2second Sunday
3third Sunday
4fourth Sunday
5last Sunday
Then press ENTER ().
To disable DST, enter the Spring month as 0.
S DST: MM SUN 
F DST: MM SUN 
Note: = ENTER
> To Review Or Change Daylight Saving Time
From the Time Display Mode:
· Press DST (#7) and then press ENTER ()
SPRING DST will appear on the display
· Press ENTER ()iftheMONTHdisplayediscorrect,orkeyinthecorrectMONTHandpressENTER (),
the cursor will advance to the SUNDAY position
NOTE: To bypass the DST feature, enter 00 and press ENTER ()
· Press ENTER () if the SUNDAY displayed is correct, or key in the correct SUNDAY and press ENTER ()
FALL DST will appear on the display
· Press ENTER ()iftheMONTHdisplayediscorrect,orkeyinthecorrectMONTHandpressENTER (),
the cursor will advance to the SUNDAY position
· Press ENTER () if the SUNDAY displayed is correct, or key in the correct SUNDAY and press ENTER (),
the display will return to the Time Display Mode

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AP21 Programming Manual
BASIC PROGRAM STEPS
— From the MAIN DISPLAY, press B(BASIC) then ENTER ().
Enter the step number, press ENTER (), and enter the program step information as illustrated below:
Day/s  HH  MM  AM/PM  ON/OFF 
Note: = ENTER
> To Enter Or Change The Basic Program Steps
From the Time Display Mode:
· Press BASIC (B) and then press ENTER ()
· Key in specific program step number (00-16) or press ENTER () to move one by one
· Press ENTER () if the day/s displayed is correct or, advance to the correct day/s by pressing DAY (#4),
then press ENTER (), the cursor will advance to the HOUR position
· Press ENTER () if the hour displayed is correct or, key in the correct hour then press ENTER (), the cursor will
advance to the AM/PM position
· Press ENTER () if the AM/PM displayed is correct or, key in the correct AM/PM then press ENTER (), the display
will advance to the ON/OFF position
· Press ENTER () if the ON/OFF displayed is correct or, toggle the ON or OFF then press ENTER (), the cursor will
 advancetothenextprogramstepnumber
· Repeat the programming process or press EXIT (#) to return to the Time Display Mode
> To Review The Basic Program Steps
From the Time Display Mode:
· Press BASIC (B) and then press ENTER ()
· Press BASIC (B) to advance through the BASIC program steps
· Press EXIT (#) to escape to the Time Display Mode
> To Clear A Basic Program Step
From the Time Display Mode:
· Press BASIC (B) and then press ENTER ()
· Key in the step number to be cleared then press ENTER ()
· Press ENTER () to advance the cursor to the HOUR
 ·Keyin00(zero,zero)fortheHOURthenpressENTER (), the program step is cleared and the display
returns to STEP 00
· Key in another step number to be cleared or press EXIT (#) to return to the Time Display Mode

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AP21 Programming Manual
> Clearing All Basic Programming
From the Time Display Mode:
· Press CLEAR (C), then ENTER ()
· Press BASIC (B) to clear all of the Basic programming
· Press EXIT (#) to escape to the Time Display Mode
ANNUAL PLAN PROGRAMMING
— Press the ANNUAL (A) key and press ENTER (), key in the
number, press ENTER (), and enter the annual plan program
as as iillustrated at right, be sure to press ENTER () after
each entry.
Note: To skip a single day, both the START date and
END date must be the same.
Note: = ENTER
START: MM DD YY 
END: MM DD YY 
> To Enter Or Change The Annual Plan Program Steps
Starting from the Time Display Mode:
· Press ANNUAL (A) and then press ENTER ()
· Key in specific PLAN number to be changed, then press ENTER (), the START date (MM-DD-YY) will be displayed
· Press ENTER () if the month displayed is correct or, key in the correct month then press ENTER (), the cursor will
advance to the DAY position
· Press ENTER () if the day displayed is correct or, key in the correct day then press the ENTER (), the cursor
will advance to the YEAR position
· Press ENTER () if the year displayed is correct or, key in the correct year then press the ENTER (), the display will
advance to the END date (MM-DD-YY)
· Press ENTER () if the month displayed is correct or, key in the correct month then press ENTER (), the cursor
will advance to the DAY position
· Press ENTER () if the day displayed is correct or, key in the correct day then press ENTER (), the cursor will
advance to the YEAR position
· Press ENTER () if the year displayed is correct or, key in the correct year then press ENTER (), the display
 willadvancetothenextANNUALplannumber
· Repeat the programming process or press EXIT (#) to return to the Time Display Mode

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AP21 Programming Manual
> To Clear All Annual Plan Programs
Starting from the Time Display Mode:
· Press CLEAR (C) and then press ENTER ()
· Press ANNUAL (A) key to clear all ANNUAL PLAN programs
· The display will return to the Time Display Mode
> To Clear A Specific Annual Plan Program
Starting from the Time Display Mode:
· Press ANNUAL (A) and then press ENTER ()
· Key in specific ANNUAL PLAN number to be cleared, then press ENTER ()
· Key in 00 (zero, zero) for the month then press ENTER (), the ANNUAL PLAN is cleared and the display
returns to 00
· Key in another ANNUAL PLAN number to be cleared or press EXIT (#) to return to the Time Display Mode
> To Review Annual Plan Program Steps
Starting from the Time Display Mode:
· Press ANNUAL (A) and then press ENTER ()
· Press ANNUAL (A) to advance through the ANNUAL PLAN program steps
· Press EXIT (#) to escape to the Time Display Mode

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AP21 Programming Manual
ACTIVATE SLEEP MODE
Starting from the Time Display Mode:
· Key in 45 and then press ENTER (), SLEEP MODE will be displayed
ENTER OR CHANGE THE PULSE RATE (BELLS, SIRENS, ETC.)
Starting from the Time Display Mode:
· Press 5and then press ENTER ()
· Press ENTER () if the pulse displayed is correct or, key in the correct PULSE (0 = steady ON,
 01to99=steadyONforXseconds)then press ENTER ()
· The display will return to the Time Display Mode
DEACTIVATE SLEEP MODE
Starting from the Sleep Display Mode:
· Key in 45 and then press ENTER (), SLEEP MODE is no longer on or visible on the display
· Press the EXIT (#) key to return to the Time Display Mode
MANUALLY OPERATE THE OUTPUT RELAY
Starting from the Time Display Mode:
ON: To manually turn the AP21 RELAY ON, press 1, then ENTER (), the display will return to the Time Display Mode
OFF: To manually turn the AP21 RELAY OFF, press 0, then ENTER (), the display will return to the Time Display Mode
TRANSFER A PROGRAM FROM ONE AP21 TO ANOTHER
Starting from the Time Display Mode:
· Key in 78, then press ENTER () on the AP21 the program will be transferred FROM
· Connect an RTC time-switch-to-time-switch transfer cable (not included) to the two time switches and press ENTER ()
on the AP21 the program will be transferred FROM
· The program will be transferred from one AP21 to the other
· The display will return to the Time Display Mode
DISPLAY SECONDS IN THE TIME DISPLAY
Starting from the Time Display Mode:
· Key in 33 and then press ENTER (), the SECONDS display will appear
· Press EXIT (#), the display will return to the Time Display Mode

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AP21 Programming Manual
lIMITED PRODuCT WARRANTY
RTC Manufacturing, Inc. (RTC) warrants its products to be free from defects in materi-
als and workmanship for a period of five (5) years from the date of purchase provided:
•the product was properly installed, used, operated and maintained; and
•the customer has proof of the date of purchase
RTC will, at its option, either repair or replace the defective product.
The customer at its cost shall deliver the defective product to RTC, and RTC will
repair or replace the product and return it to the customer at RTC’s cost.
RTC will not be responsible for damage caused by electrical surges, brownouts,
blackouts,lightningoranyotheractofGodorelectricalevent.
PRODuCT ExCEPTIONS:
—CellularModemequipmentcarriesthesamewarrantyabove,exceptthetermisfor
 aperiodoftwo(2)years.Extendedmodemwarrantiesareavailableforpurchase.
—RadioEquipmentcarriesthesamewarrantyabove,exceptthetermisforaperiod
of one (1) year.
—Batteriescarrythesamewarrantyabove,exceptthetermisforaperiodof
two (2) years.

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SERVICE It is recommended that all service for theAP21 be performed by the factory or by a factory-authorized
service representative.
CAUTION: If you repair your AP21 time switches without factory support, please note that before
removing or replacing any IC1 or IC2, the 1 FD super capacitor must be totally discharged to avoid
damage. On the left side of the printed circuit assembly, there are two test points. One is ground and the
other is the super capacitor connection. Use a clip lead to short these test points together to discharge
the super capacitor. It is recommended that the clip lead be left in place until the repair is completed.
RTC Manufacturing, Inc. is committed to provide ongoing service support for time switches in or out of
warranty. Please ship your repairs freight prepaid to the dealer in your area, or directly to:
RTC Manufacturing, Inc.
1016 Enterprise Place
  Arlington,Texas76001
If the customer/end user ships directly to RTC, shipping charges will be paid by RTC for repaired
products returned to the customer/end user via regular surface freight. Overnight delivery must be
requested in advance and will be billed to the customer/end user.
THEORY OF
OPERATION
The AP21 is a microprocessor based device. Because of the large scale integrated circuits used, there
are only three (3) ICs that make up the time switch.
IC1 is a 6805 type microprocessor with built-in RAM and ROM. The built-in RAM is used for storing
the time, date and program information. The built-in ROM contains the AP21 operating software
(approximately4kb).ThesoftwareoftheAP21timeswitchiscopyrighted.Reproductionsofany
kind are strictly prohibited by law.
IC2 is the real time clock. This circuitry is used only during power failures to keep time until
power returns.
Schematics and Parts List are available directly by request by contacting RTC.